lcd, head sensor temperature display

[Chamarejc]

Hi all,
I meet a mysterious problem with my gt2560 and ReprapDiscount smart controller.
At power on the head temperature is not displayed and show "ady./0°".
To get the right one I have to do -> prepare -> switch power off and then the temperature is displayed.
If I come back to switch power and change the state to on all is nominal and runs correctly.
Has someone an idea about this ?
Thanks for answer.

[William]

Hi,could you take some pictures about it to show more details?